if 5 > 2:
    print("hello world")
else:
    print("error")
age = 30;
if age < 18:
    print("未成年")
elif age >= 18 and age < 30:
    print("年青人")
elif age >= 30 and age < 50:
    print("中年人")
elif age >= 50:
    print("老年人")

# #判断闰年
# year = int(input("请输入年份："))
# if (year % 4 == 0 and year % 100 != 0) or (year % 400 == 0):
#     print("%d是闰年" % year)
# else:
#     print("%d不是闰年" % year)


# a b c比较大小
a = int(input("请输入数字a:"))
b = int(input("请输入数字b:"))
c = int(input("请输入数字c:"))
if a > b:
    if a > c:
        print("a is the largest")
    else:
        print("c is the largest")
else:
    if b > c:
        print("b is the largest")
    else:
        print("c is the largest")

# 计算器实现加减乘除
num1 = float(input("请输入数字1"))
num2 = float(input("请输入数字2"))
op = input("输入运算符")

if op == "+":
    print(num1 + num2)
elif op == "-":
    print(num1 - num2)
elif op == "*":
    print(num1 * num2)
elif op == "/":
    print(num1 / num2)
else:
    print("输入错误")
